local cmp = require 'cmp'
local context = require 'cmp.config.context'

vim.o.completeopt = nil

-- Plugin helper
local feedkey = function(key, mode)
  key = vim.api.nvim_replace_termcodes(key, true, true, true)
  vim.api.nvim_feedkeys(key, mode, true)
end

-- General setup
cmp.setup {
  snippet = {
    expand = function(args) vim.fn['vsnip#anonymous'](args.body) end,
  },
  window = {
    documentation = { border = 'rounded' },
  },
  formatting = {
    fields = { 'menu', 'abbr', 'kind' },
    format = function(entry, item)
      item.menu = ({
        nvim_lsp = 'λ',
        vsnip = '⋗',
        buffer = 'Ω',
        path = '🖫',
      })[entry.source.name]
      return item
    end,
  },
  preselect = cmp.PreselectMode.None,
  mapping = {
    -- Confirm, jump or select with tab
    ['<tab>'] = cmp.mapping(function(fallback)
      if cmp.get_selected_entry() then
        cmp.confirm()
      elseif vim.fn['vsnip#jumpable'](1) == 1 then
        feedkey('<plug>(vsnip-jump-next)', '')
      elseif vim.fn['vsnip#expandable']() == 1 then
        feedkey('<plug>(vsnip-expand)', '')
      elseif cmp.visible() then
        cmp.select_next_item()
      else
        fallback()
      end
    end, { 'i', 's' }),
    -- Jump back with shift tab
    ['<s-tab>'] = cmp.mapping(function(fallback)
      if vim.fn['vsnip#jumpable'](-1) == 1 then
        feedkey('<plug>(vsnip-jump-prev)', '')
      else
        fallback()
      end
    end, { 'i', 's' }),
    -- Navigate options with ctrl-n and ctrl-p
    ['<c-n>'] = cmp.mapping(function(fallback)
      if not cmp.visible() then
        cmp.complete()
      else
        cmp.select_next_item()
      end
    end),
    ['<c-p>'] = cmp.mapping(function(fallback)
      if cmp.visible() then
        cmp.select_prev_item()
      else
        fallback()
      end
    end),
  },
  sources = cmp.config.sources({
    { name = 'nvim_lsp' },
    { name = 'vsnip' },
    { name = 'nvim_lua' },
  }, {
    { name = 'buffer', keyword_length = 5 },
    { name = 'path' },
  }),
  completion = {
    keyword_length = 3
  },
  -- Disable in comments
  enabled = function()
    return not context.in_syntax_group('Comment')
  end,
}